This invention relates to memory controllers. More particularly, this invention relates to providing different signal functionality on the same pins of memory controller circuits.
Computer circuits typically include a CPU (central processing unit) and at least one memory controller, which controls communications between the CPU and various memory components. Computer circuits are usually implemented on a printed circuit board where board space is often an important design consideration. One way to save space is to reduce the pin count on integrated circuit chip packages. One way to reduce pin count on chip packages is to reuse, where possible, the same pins for multiple purposes.
Reduction of pin count is often sought in memory controller circuits because they are generally larger chip packages. However, the advent of wide address/data paths and of numerous types of memories that need to be accommodated by memory controller circuits has resulted in an increase in the number of pins on memory controller chip packages. Moreover, although memory controller circuits are designed to accommodate various types of memories, and can therefore be used in different types of computer circuits, such as, for example, workstations and personal computers, not all applications will include those types of memories. This may result in unused memory controller chip package pins, thus wasting valuable circuit board space.
In view of the foregoing, it would be desirable to provide a memory controller that can be coupled to different types of memories without requiring additional memory controller pins or resulting in unused pins.